If you reformatted it and everything is gone, then a recovery program like the one mentioned above will probably get most of the data back.
If you have dropped, shook it while it was running and no longer works, then you will have to send it in to a specialist to recover the data. Will likely cost a fair bit of money.
If the drive has been significantly damaged and/or the chassis of the drive is bent inward, then it is likely that platter inside has shattered and there is nothing you can do.
To test for this, carefully shake it (unplugged of course) and listen for anything rattling around in there.
I recover data for friends on a pretty regular basis and I can take a look at it for you if you live in the US. You pay shipping both ways. If I can't recover anything for you, you don't pay anything else.
"MANIRAJ", a little bit late reply but hope you can still hear. ^^
You can try third party mac recupero dati utility. I have faced the same situation few moths ago but with hte help of this utility i was able to recover my all the data from hard drive.